In the case of a fracture of the femur, particularly in adults, it is relatively common to utilize internal fixation of the bone to stabilize the fracture site or sites and to facilitate healing. One such technique is closed intramedullary nailing in which an elongated implant, such as a rod, nail, pin, or the like is inserted longitudinally through the intramedullary canal of the bone. The procedure normally involves making a small incision in the buttocks and entering the canal of the femur through the lower portion of the greater trochanter. A guide pin is inserted and a cannulated flexible reamer is passed over the pin. The canal is enlarged by reaming through the upper portion of the femur, then along the canal, across the fracture site, and into the lower portion of the femur, whereupon the rod is driven into the canal.
Reaming of the canal is normally accomplished with flexible reamers and a rotatory drill during the surgical procedure. The procedure may be used for proximal, mid-shaft or distal fractures and in many cases, for oblique and segmented or comminuted fractures. The surgeon utilizes fluoroscopic imaging during the reaming procedure and placement of the rod to ensure proper reduction of the fracture and the proper depth and placement of the rod. It is important to avoid eccentric reaming of the canal which can result in comminution at or near the fracture site. Since the reamers are long and flexible and usually must curve away from the torso of the patient when in use, it will be appreciated by those skilled in the art that avoiding eccentric reaming is a precise and demanding task. It is to the facilitation of this task that the present invention is directed.